OD trans behind a 273

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If you opt for an auto, go with a 200R4, it has the least amount of work to install in a 67-76 a body.
 
Another factor to keep in mind is that you might need to have a custom torque converter made. From my reading here it is my understanding that the register in the crankshaft changed the same year the number of input splines changed on the automatic transmissions. When putting a late engine in front of an earlier transmission there is a spacer that you can purchase to fill the gap but options for a late transmission with an early engine are limited.
 
Thanks Fishy68, I as the question before i read enough. I see the a500 was the OD version of the 904. That's what I would like to have. What car / truck do I need to look for to find one?
Tom
 
A long time ago someone posted that hp and torque numbers for a stock 273 suggest overdrive would put you out of the engines power band unless at least a certain rear gear ratio was used. With the lower rear gear the fuel milage, engine rpm at highway speed, etc.. remained pretty much unchanged with overdrive.
 
RedFish said:
A long time ago someone posted that hp and torque numbers for a stock 273 suggest overdrive would put you out of the engines power band unless at least a certain rear gear ratio was used. With the lower rear gear the fuel milage, engine rpm at highway speed, etc.. remained pretty much unchanged with overdrive.
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I wouldn't doubt it. You'd probably need to run at least 3.55~3.73 gears or it wouldn't work good at all.
 
easyrider said:
Thanks Fishy68, I as the question before i read enough. I see the a500 was the OD version of the 904. That's what I would like to have. What car / truck do I need to look for to find one?
Tom
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No problem Tom. Ma Mopar never used them in any cars at all. Just trucks like mentioned above.

Have you also read up on how much work it is to get one in an A-body?
 
fishy68 said:
No problem Tom. Ma Mopar never used them in any cars at all. Just trucks like mentioned above.

Have you also read up on how much work it is to get one in an A-body?
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I read the link above and I am not cutting my car up to do it but my car isn't ever going to be a daily driver either.
 
In the grand scheme of things, its not that much work to chop, template and weld for the a500, it's if you want to do it. For the OP there may be some other issues narrowing his selection a bit, as others have said. Good luck on the research!

Here is a link that may help:

http://www.dippy.org/forum2/index.php?topic=231.0
 
Thanks Fishy68, I have read that artical and some others. I guess the 273 / od combo is not a good idea. May not mater at this point, today I found an issue with the 273. Water leaking at the intake / head between 3 and 5 cylinder area. I've been wanting a 360 anyway. this maybe the time. My wife thinks this thing is a BOAT. (Bring Out Another Thousand)

Tom
 
Your welcome Tom. A 360 is a huge improvement in torque so you can run a lot taller gears with it and not need a od. I'm not knocking the 273 but it's small cubic inch does make for a challenge getting real good perf. along with driveability since it's more of a high rpm engine.
 
That is the great part about a OD trans- you can run 3.91-4.10 gears and still drive the car on the highway- I have 4.30 gears in my T-5 mustang w/ a 275/60/15 (28") tire it's at 3,000rpm @70mph

Durango's, and the like come with 3.55 or 3.90 gears and my personal Durango has 3.55's and cruising @60mph it's only at 1,800rpm's that's with a 46RE (electronic 727 w/ OD is basically what it is) and a 31" tire -only thing that sucks about it IS you need the ECU from the truck to control it, and a SCT tuner (and a tune from Sean) to tune the shift points or you're stuck with a 4,800rpm shift points
 
I used an earlier lock up from a late 80's diplomat with a 1 wire button activated OD & lower 1st & 2nd gears. These were also found in van's & trucks & didn't need a computer to work the OD
 
Sedanman said:
I used an earlier lock up from a late 80's diplomat with a 1 wire button activated OD & lower 1st & 2nd gears. These were also found in van's & trucks & didn't need a computer to work the OD
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I could be wrong but I don't believe they ever used an OD trans. in Diplomats, or any V8 cars in the late 80's. Just trucks had OD trans. I believe all they ever had was a 904 lockup trans. in cars. A lockup trans. isn't the same as an OD trans. It just locks up the converter so it doesn't slip. It'll drop the RPM a couple hundred at most while an OD will drop it several hundred or more.
 
Ah,you may be right. It could be out of an 87 van with the push button for the od. There is a solenoid on the valve body
 
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